With such backends you need to tell the backend that the origin is https,
otherwise it will 'think' its serving http since it is unaware of a proxy.
ea.
<!-- This connector is for normal HTTP connections -->
<Connector port="8080" protocol="HTTP/1.1"
proxyPort="443"
proxyName="domain.nl"
You might get away with a static set host value.
Posted at Nginx Forum: http://forum.nginx.org/read.php?2,254615,254618#msg-254618